Automatic sighting mechanism eos



Jam. l5 11924., RASLZQL@ E. A. SPERRY AUTOMATIC SIGHTING MECHANISM FOR AIRCRAFT- GUNS Filed Dec. 22 1917 3 Sheetshee: E

Jam. 15 1924!@ EASLZ E. A. SPERRY AUTOMATIC SIGHTING MEGHANISM FOR AIRCRAFT GUNS Filed De. 22 1917 3 Sheets-Sheet 2 Jan. l5 11924@- Y 1,4811,248 E. A. SPERRY AUTOMATIC SIGHTING MECHANISM FOR AIRCRAFT GUNS Filed Dec. 22, 1917 3 sheets-sheet s IN l/E/V TOI? enteramente, i924.

ELMER A. SPERRY, 0F BROQKLYN, `NEW YORK.

AUTOMATIC SIGHTING- MECHANISM FOR AIRCRAFT GUNS.

Application tiled December 22, 1917, Serial No. 208,390.

T 0 all whom t may concerne.'

Be it known that I. Emma A. SPERIiY, a citizen of the United btates of America, residing at 1505 Albemarle Road. Brooklyn, in the county of Kings and State of hcw York, have invented certain new and useful Improvements in Automatic Sighting Mechanism for Aircraft Guns, of which the following is a specification.

This invention relates to gunsighting devices7 Inore specifically to a sighting system for anti-aircraft guns and in its most specific aspect to a sighting system for guns adapted to be tired from one aircraft at another.

It is extremely difficult to hit a rapidly moving,` target. such as an aeroplane, even from a fixed base due to the fact that the range and bearing of the target are continuously and rapidly varying and deflection of the bullet or shell by the wind takes place. When the gun is -tired from one aeroplane at another the diicnlty of making a hit is further increased.

One of the principal objects of my invention is to provide a means for shifting the sight with respect to the gun so that by keeping the sight on the relatively moving target the gun will be automatically pointed in such a direction as to hit the target.

Another Objectis to provide a novel form of means for obtaining the rate of change of relative bearing of a gun and its target.

A further object is to providemeans for automatically deflecting the sight Withrespect to the gun for introducing a correction due to the relative velocity of the wind with respect to the gun mount. Other objects and advantages Will appear as the invention is hereinafter developed.

Referring to the drawings which illustrate What'I now consider the preferred form of my invention:

Fig. 1 is an elevation of n'iy invention applied to a machine gun.

Fig. 2 is a plan view of the structure shown in Fig. 1.

Fig. 3 is a sectional elevation of the sighting device and its support, taken on the line 3-3 of Fig. 4.

Fig. 4: is a fragmentary sectional detail taken on the line 4 4 of Fig. 3.

Fig. 5 is a section taken on the line 5--5 of Fig. 4.

Fig. 6 is a fragmentary end elevation of the structure shown in Figs.v 1 and 2.

Fig. 7 is an elevation, partly in section, of one form of 'speed responsive device and follow-up forming a part of my invention.

lFig. 8 is a planview of a part of the mechanism contained in the casing 3 of Figs. 1 and 2.

Fig. 9 is a plan view of thc remaining mechanism contained in the casing 3, the upper part of the speed responsive mechanism being removed.

Fig. 10 is a detail elevation of the differential Shown in F ig.'9.

Fig. 11 is a detail sectional elevation taken on the line 11-11 of Fig. 8, the crank pin 102 being shown in a different position.

Fig. 12 is a sectional detail elevation taken on the line 12-12 of Fig. 9.

Fig. 13 is a diagrammatic view employed in explaining the theory of operation of my invention.

Fig. 14 is a fragmentary plan view of a.

part of the mechanism illustrated in Fig. 9,' certain of the elements ,being in a different position. v

Fig. 15 is a fragmentary sectional elevation taken von the line 15-15 of Fig. 8.,

Fig. 1G is a detail elevation looking in the direction of the arrow 16 in Fig. 8.

1n order to hit a moving target by means of a projectile fired from a gun, it is necessary to aim the gun ahead of the position occupied by the target when the gun is fired.

Neglecting certain factors such as deflection due-to windage, etc., this angular deection necessary is equal to the rate of change of relative; bearing of the target multiplied by the time of flight of the projectile. lVhile these various factors may be determined and multiplied in various ways., I prefer to employ the structure illustrated which comprises means automatically positioned in accordance with the rate of change of relative bearing of the target, when the gun sightis kept on the latter; means for setting the sight in elevation in accordance with the. range; means connected to the last. mentioned means for combining the position ofthe first mentioned means with a function of the range (time of flightl of the projectile) and means for automati. Acally deliect-ing the gun with respect to the sight in accordance with the product of rate of change of relative bearing and the time of Hight of the projectile.

It will be seen that I have illustrated `the gun in the form of a machine gun 1 pivot- A vcupslriaped member 19 offnon-magnetic ally mounted about a horizontal axis 2 on a casing 3 in turn rotatable about the normally vertical spindle 4 iixedly carried \by the gun mount 5. rlhe un l is also shown as rovided with a siglit dwhich vshould pre erably be either a wide angle or open sight. For determining the rate of change of relative bearing factor the following structure is preferredy at this time.

A gear wheel 7 (see Figs. G and 8) is fixedly carried by the spindle t within the cas- 14 secured to casing 3, is provided with a' ing 3 and is adapted to cause rotation of kai. shaft- 11 through a suitable train oi gearing 7, 8, 9, 10, said elements 7 to l1 beine' carried by the casing 3. The shaft 11, s own as journaled in bearings 13, 13 in a frame plurality' of permanent magnets 15, 16, 17 adapted to rotate withinan, annulus 18 of magnetic material, secured to said trame 14.

electrical conducting' material is oscillatable between magnets 15, 16, 17 and the annulus 18, said membery 19 being mounted on a shaft 20 which telescopesand is journaled at one end within the shat't 11 and which shatt20 is y'ournaled at its other end in a member 21 xedto frame 14. The member 19 is shown biased to normal central position by means of a pair of oppositely'coiledv springs 22, 23 mountedwithinand secured at one endv to a housing 211,- carried by said ymember 19, the other ends of said springs being secured to the' relatively fixedmerm ber 2l. To keep the sight 6 on thetarget the gun 1 is swung about its kvertical axis causing shaft 11 to be rotated and if the said sight is continuously kept on the target the shaft 11 will be rotated at a rate proportional to the rate of change of relative bearing of the torqueof the member 19 is comparativelyl small, I prefer to connect this member to the mechanism, it is employed to actuate, through a fo1low-u connection. While various forms of fo low-up systems may be employed I refer at present, the one illustrated in Figs. 7 and 9, which is entirely mechanical and constructed substantially as follows:

An arm 25 is secured to said member'19 .and has pivotally .connected thereto at its inner end an arm 26 which is secured at the outer end to a shaft 27 rotatably mounted in Asume various forms but prefa Laenaaa the outer end of arm `28. The last'men-y tioned arm is shown secured to a rectangu-` lar portion 38 cfa shaft 39 rotatably mounted at one end in a journal Lit) carried by 3() normally out of mesh with but adapted to engage respectivell the ratclicts 3l, r0- tatably mounted wit respect to each other andrwitli respect to the shaft 39 on which they are mounted. The last mentioned ratchets are preferably continuously rotated in opposite directions by means of a beveled pinion 35 meshing with a beveled gear portion 33 of gear 32 and with a beveled gear 34 secured to thehub ofgear 3l. The pinion 35 may be secured toa shaft 36, journaled in a bracketvto the casing 3, which shaft maybe continuously rotated by any suitable motor such as a spring motor 37.

t rl`he operation of my follow-up may best beunderstood by inspection oflig. 9. lt

themember 19r is deected in a counterclockwise direction (looking down in Fig. 7) the arm 25 will move in the same direcy tion causing .the inner end of the arm 2o to assume momentarily a position to one side yof itsvnormal position. This movement of arm 26 will rotate the shaft 27 to cause one or the other of the pawls to cngageits corresponding gear wheel. Under the assumption made above, the pawl 30 will engage gear 32, which is rotating in the direction of the arrow, thuscausing the arm 2S to be moved; in a counterclockwise direction untilv it is directly under the arm 25 when the pawls 29, 30 Will assume the position indicated in dotted Y,lines in Fig. 9 and movement of arm 28 will cease. Movement ot the arm 25 in a clockwise direction will cause thev pawl 29 and gear 31 to come into action to move the follow-up arm 28 in a clockwise direction. lln short, the clock train 37 will supply energy to arm 28 to cause the latter to follow-up the movements of arm 25.

Thev means for setting the sight i-n elevation inv accordance with the ran emay asly the setting should be accomplished f om the casing 3. A preferred form of mech nism is indicated`in Figs.A 1 to 5 and 9. A shaft 45 is shown journaled in casing 3 and terminating at its opposite ends in a thumb nut 46 and a flexible sha-ft 47. The latter is journaled at its-other end in a bearinoflffixedly secured to the sight 6 and xedly carries at that a beveled pinion 48. The last mentioned element 48 meshes with a beveled gear 49 rotatably carried by the sight 6 and provided with a downwardly extending member 50 having .n internal projection 50'l adapted to engage a suitable cam groove 51 in a member 51. The last mentioned zol als

memes member is shown as fixed to the base member 54, to which the sight is horizontally pivoted at 56 by means of a pin and slot connection 52, 53. Obviously rotation of the V4thumb nut 46 will cause the sight to be raised or depressed, depending on the direction of turning of said nut, through the connections above described, but this would raise and lower the si ht with respect to the target. Since the sig t must necessarily be held on the target at all times, the gun is raised or lowered by the "operator with respect to the target. Thus, if the screw-46 is turned so that ordinarily the sight would be raised 2, the sight is held on thev target while the gun and base 80 are elevated 2, the screw 51 traveling upwardly in member 51.

In order to inform the operator of the range for which the sight is ad'usted in elevation I provide suitable indicating means which I prefer to mount in a 'positlon visible to the operator when the `latter is looking through the sight 6. Thus a disk 57 extending into the sight 6 and properly calibrated to range may be carried by a shaft '58 journaled in a bearing 59 carried by the sight 6. The shaft 58 carries also a beveled pinion 6() which meshes with a beveled pinion 61 secured to gear 49. The disk 57 may be read, with the vertical cross-hair 62 of the sight 6 as a reference line to indicate to the operator the range for which the sight is set in elevation.

The means fory combining the rate of change of relative bearing with the time of flight of projectile (a function of the range) may assume the form shown in Fig 9. The shaft 89, which is positioned in accordance with the rate of change of relative bearing, is provided with a pinion 62 which meshes with the segmental end 63 0f a slotted lever 64 pivoted at 65. The slotted lever 64 is Vadapted to actuate a similar slotted lever 64', pivoted at 65', by means of a pin 66 passing through the slots of both of said levers 64, 64. It will be seen that the lever 64 will impart movement to lever. 64 proportional to themovement of said lever 64 and the ratio of movements of said slotted levers will depend on the position of the pin 66 with respect to the fulcrums 65, 65.

Mechanism is provided for positioning the pin 66 with respect to fulcrums 65, 65 in accordance with the angular setting of the shaft 45 as indicated on the range .scale 57. A plate 67 is slidably mounted on the base of casing 3 ,by means of fixed pins 69 cooperating with slotted extensions 68 secured to said plate 67. The plate 67 is provided with a slot 70 in which the pin 66 is constrained to move and is also provided adjacent one edge with a rack 71 which meshes with a gear 72 rotatably mounted on a spindle 73 (see Fig. 12) tixedly carried by a bracket 74 mounted in casing 3. The shaft 45 which is f rotatably journaled in the bracket 74 carries a'beveled pinion 75 which meshes with a beveled pinion 76 secured to the gear 72.

By virtue of the above described structure it will be seen that the pin 66 is positioned with respect to the fulcrums 65, 65

inr accordance with a function of the range as indicated on the dial 57 and the arts are so designed that with an even ca ibration of the range dial 57 the position of said pin 66 is in accordance with the time of flight of a projectile (of the gun employed) to a target at the range indicated. Thus the lever. 64 will be given a position in accordance with or depending on the product of the rate of change of relative bearing and the time of flight of the shell. The lever 64', may, therefore, be employed to deflect the gun wth\respect to its sight so that when the latter is held on the target the gun will be pointing ahead of the target an an ular distance necessary to cause a projectie to hit the latter. (Neglecting the el'ect of wind deflection.) One form of mechanism for effecting this connection is illustrated in Figs. 1 to 5, 9 and 10, and is constructed substantially as follows: l

The sight 6 as previously described, is carried b a platform or base 54 (see Figs. 3 to 5) andI this base is rotatable about a normally vertical axis with respect to the base 80 which is secured to the gun 1. Preferably the. upper base should overlap the lower one so as to form a. box-like water-tight container for the adjusting mechanism adjacent the sight. For adjusting the sight 6 about the normally vertical axis above mentioned the upper base 54 may carry a worin rack 81 which meshes with a worm 82 rotatably carried by the lower base. 80 in brackets 83 secured to saidv lower base.. The shaft of y the worm is shown connected to a flexible shaft 84 which terminates at its opposite end within casing 3. Preferably, for a purpose which will hereinafter appear, the connection between the lever 64 and shaft 84 should be through a differential. One form of differential is shown in Figs. 9 and 10 as comprising three arms. One a m comprises a gear wheel 85 ixedly secured to a spindle 86 rotatably mounted at 88 in a bracket 87 secured to the casing 3. The gear 85 meshes with a pinion 89 fixed on shaft 84 journaled at. 90 in, the bracket 87 and carries on two of its spokes the beveled gears 91 which are rotatable with respect to said spokes.- The last mentioned gears mesh with beveled gears 92, 93 rotatably mounted on the s indle 86 and each secured to a correspon ing gear 94, 95. The gear 94 meshes with the segmental lever 64. Assuming that .the gear 95 is held against rotation and ignoring for the time being the effect of wind defleclll tion the operation of my invention as thus far described is substantially as follows:

'lhe gun l is moved in such a manner as to keep the sight 6 continuously on the target. The operator then adjusts the nut 46 until the indication of the dial 5T opposite .the cross-hair 62 corresponds to the range of the target which may be ascertained in any suitable well-known manner. Theadjustment of the nut 46 sets the sight for the elevation corresponding to the rangey and also positions the pin 66 in accordance with the time of night of the projectile for the range indicated. The member 63 is positioned. automatically in accordance with the rateof change of relativebearing of the target and gun and the lever 64', which combines the displacements of the pin 66 due to the movements of plate 67 and llever 64, rotates the Hexible shaft 84 to an extent and in such a direction as to cause the gun to lead the sight (or the sight to lag behind the gun) an angular distance equal to the rate of change of bearing multiplied by the time of ight of the projectile.

The above operation however, as previously stated, ignores the effect of wind dei'lection on the projectile. l prefer, however, to correct for this factor, also as the relative velocity of the wind and aero lane,

if the gun is fired from an aerop ane) Awhich l will term the air-speed,*is much higher than the same velocity when the gun is fired from a fixed base. The effect of the air speed on the path of the projectile may hev and as the an le t is comparatively small sin t may be p aced equal to t so that equation (I) becomes:

(II) :Jg sin p Let it assumed that the angle p is equal tothe angle a, which is approximately correct. Equation (II) then may be written:

(III) which means that the deflection of the' prow t=5 sin a,

jectile due tothe air-speed for a unit milenaria terval of time is approximatelyequal to the product of a function 4of the air-speed, the reciprocal ot' the muzzle velocity of the-projectile and the sine of the angle between the `gun and the line of Hight of the aircraft on which the gun is mounted. Obviously the angle through which the gun 1 must be defiected with res ct to its sight 6 to allow for the wind de ection is numerically proportional to angle t. Furthermore, when the gun is being pointed at a target to the side l of the line of Hight the sight 6 must be shifted an angle proportional to z5 in a counterclockwise direction with respect to the gun to correct for wind dedection. lf the gun is pointed to the opposite vside of Y the sight must be shifted in a clockwise direction with respect to the n. Calling attention to Figs. 8, 11, 14 an( 15 it will be seen that l have provided a meansu for automatically Jpositioning a part in accordance'with the sine of the angle a between the gun and the longitudinal axis of the guns-supportingk aircraft and in the proper direction. gear wheel 100 of the same size as fixed gear wheel 7 meshes with the latter and is rotatabl suported in casing 3 on a shaft 101 (see llig. 11). A crank pin 102 on gear 100 engages in a slot 103 in a member 104 which is provided with a cross-piece 109 forming the connectin iinli of a pair of links 105, 106, of equal ength and pivoted at 107 and 108 respectively (see Fig. 8). The cross-piece 109 besides having pivoted thereto the links 105, 106 carries at its'middle a pin 110 towhich an arm 111 is connected at one end, the opposite end of saidarm 111 being rovided with a slot 112 engaged by a xe pin 113 carried by a bracket 114. The arm 111 is slotted and connected to a slotted arm 116, pivoted at 117, by means of a link 115 slidably connected in the slots of said arms 111, 116. The link 115v is preferably provided with a plurality of downwardly extending pins 118 .(see Fig. 15) which a slot 119 provided in an extension 120 yprovided on a. late 121 which will hereinafter be describe in greater detail.

Assuming that the plate 121 is stationary in the position shown in Fig. 8 with the links 105, 106 parallel to each other and assuming further that the gun is so mounted on the aircraft that the 'arrow shown on the gear 7 is pointing directly ahead, it will be seen that the movement of the gun and consequently the casing 3 aboutv the' axis of the spindle 4 will displace the arm 116 an amount proportional to the Sine of the algle a, above mentioned, inl one direction or other depending on which side of the line of flight of the gun-supporting air-craft the gun is swung to. The maximum deiection or displacement 'of the arml1 16 with the structure thus fardescribed occursY when are adapted to slide in CFI a is equal to 90o which is indicated by -the dotted line position of the parts 104, etc., in Fig. 8. This dotted line position represents the position of' the parts with respect to the casing` 3 when the gun is rotated counterclockwise as viewed in F ig. 8. l

Returning now to vEquation IU it will be seen that the angular correction of the sight to' correct for wind deflection is not only proportional to the sine of the angle a but also to the air-speed. Remembering that for any specific gun the muzzle velocity .s is approximately constant it is obvious that the angular' deflection necessary to correct for wind deflection is proportional to the product of the air speed io, angular position a and a constant.

1n order to combine the factor sin a and the air speed yw 1 provide means for moving the plate 121 and consequently the link 115 in accordance with thc air speed. The plate 121 is constrained to move in a direction parallel to the axis of' the gun 1, as by means of slotted guides 124. 125 carried by said plate 121 andcooperating with pins 122 and 123, respectively, fixed to the casing 3. The plate 121 may be adjusted by means of a. thumb nut 46', on the exterior of casing 3 land connected through gears 75', 72 to a rack 126 on said plate, said elements 46', 75 and 72 being similar to the members 46, 75 and 72 shown in Fig. 12. An indicator may be provided to aid the operator in adjusting the nut 46. Thus calling attention particularly to Figs. 8 and 16 it will be seen that 1 have provided al pointer 127 on nut 46 adapted to cooperate with a dial 128 on casing` 3, which dial 128 may be calibrated to air-speed of the gun-supporting vehicle. lt will he seen that by adjusting the nut 46 to the' air-speed (w) the position of link 115 with respect to the pivots of the arms 111 and 116 will he so adjusted as to cause the displacement of the arm 116 to be in accordance with the product of air-speed (w) and the sine of the angle of the gun displacement (sine a). f

As previously pointed out-'this setting arm 116 is not accurate to accomplish the function intended due to the factI that the angles (t and p (.see Fig. 13) which were assumed to be equal, are in fact not equal at all times. To view the problem from a differentstandpoint, it. will be seen on inspection of Fig. 13 and quations II and HI that the maximum displacement of the arm '116 from central position should occur when p is equal to 90; i. e., when the angle a is less than 900. To state this in still another way, other conditions being` the same. the maximum deflection of the projectile due to the w-ind, or more accurately the airspeed. will occur `.when the gun is aimed ahead of the athwartship position. i. e.. when angle a is less than 90. From Equation l1 .it will also be seen that the position of the gun at which the maximum deflection of projectile occurs depends on the airspeed (1w). I have, therefore, provided means for causing the maximum displacement of, the arm 116 to occur an angular amount forward of the athwartship posiltion of the gun 1 dependent. on the air speed One form of such means is shown in Figs. 8 and 14 and constructed substantially as follows:

`The plate 121 is provided with a pair of diverging slots 130 through which the pivots 107, 108 of the links 105, 106 pass. The last mentioned pivots pass also through slots 131 in plates 132 fixed to casing 3. Then the plate 121 is moved toward the rightA (Fig. 8) in accordance with the air speed the pivots 107 and 108 will be moved farther apart sothat the member 104 instead of' moving parallel to itself will be shifted through an angle with respect to its normal central position as the gear 100 ro tates. Thus when the gun 1 and-easing 3 are rotated to an athwartship position the parts will assume the position indicated in Fig. 14. The maximum displacement of the member 104 and 'consequently arm 116 does not occur in this position but when 'the gun is at an angular distance t ahead of this position. By Virtue of the above described mechanism it will 'be seen that by setting the thumb-nut 46 to the air-speed,

the displacement of the arm 116 may at all times be made substantially proportional to the product of the air speed (w) and the sine of the sum of two angles, which angles are the wind deflection angle (t) and the angle (a) of displacement. of the gun. 1n short the displacement of arm 116 is at all times substantially proportional to fw sin p (Equation I1) and as the muzzle velocity is a constant for any specific gun it will be seen that the displacement of said arm 116 will 'be proportional to t (see Equation I1 and Fig. 13). In the description up to this point the deflection of the projectile due to the relative wind has been discussed from the standpoint of deflection in a unit interval of time. The total wind deflection of the projectile is however a function of the time of flight yof the projectilewhich in turn is a function of the range. 1 therefore provide means for combining the displacement or'movement of the arm 116 with the time of flight, or in other words with a function of the range. This means may assume the form illustrated in Figs. 8 and 9.v

The free end of the arm 116 is shown pivotally connected to one end' of a link 135 whichv is rovided at its other end with a pin 137 shdable in a slot 138 in a segmental lever 139 pivot-ed at 140.-. A link 136 is shown connected at one end to the plate 67 and at its other end to an intermediate portion of the link 135 through a. reversing lever 400 and. a link 401. Bearing in mind thatthe position of the plate 67 is in accordancewith the time of flight of the projectile it Will be seen that the position or displacement of the lever .139 will at all times correspond to the total angular deflection of the projectile under the conditions of air-speed, time of Hight and angu- V lar displacement of the gun existingoat that time. 0r to state this in another Way the displacement of lever 139 will be at all times proportional to the product of w sin a and the timev of fiight of the projectile. The lever 189 may therefore be employed to deflect, automatically, the sight 6 with respect to its gunl an angular amount necessa to counteract or neutralize the angular l(Ieflection of the projectile due to the Wind.

Referring to Figs. 9 and 10 it Will be seen that the segmental gear 141 meshes Wit-h the gear 95 of the differential so that the latter combines two factors, one the angular displacement of the sight 6, with respect to gun 1, made necessary due to the change in relative position of the gun and target, and the other, the displacement necessary to correct for wind deflection.

It will now be clear from the above descrip-tiolifthat if the gun operator swings the gun 1 so as to keep the sight 6 on the target, adjusts the nut 46 to the air-speed of his oWn vehicle and the nut 46 until the range of the target is indicated at 57-62, the gun Will occupy such a position as to cause the projectile to strike the target when the gun is fired.

The entire mechanism shown in Figs. 8 and 9 is preferably contained in the casing 3 and as the mechanism adjacent the sight 6 is contained in the box like container` 54, it will be recognized that I have provided a compact, water-proof device for greatly increasing the accuracy of gun fire from one aircraft at another or from a fixed base at an aircraft. n

I have not shown my invention mounted on an aircraft as a preferred means of so mounting the gun has been made the subject matter of a separate application filed by me on January 12, 1918, Serial No. 211,472. It will be understood that my invention may be applied to any of the existing types of guns or aircrafts vprovided that the gun-mount is so positioned that the arrow shown on the gear 7 in Fig. 8 points in the direction of the line of flight of the aircraft on Which it is mounted. If desirable the nut 46 may be provided with a pointer 62 adapted to cooperate with a dial 57', similar to dial 57 except that the former is fixed, to indicate the range for which the apparatus is set.

iastate In accordance with the provisions of the patent statutes, I have herein describedthe principle of operationof my invention, together with the apparatus, which I now consider to respresent' the best embodiment thereof, but I desire to have it understood that the apparatus shown is only illustrative and that the invention can lbe carried out by other means. Also, While it is designed to use lthe various features and elements in thecomlgination and relations described,'some of these may be alteredand others omitted Without interfering with the more general results outlined, and the invention extends to such use.

Having described my invention, what I claim and desire to secure by Letters Patent is:

1.111 combination, a gun sight, a support therefor, mens adapted to be set in accordance Wit the range of a target, means actuated in accordance with the angular velocity of said sight relative t`o said support and means controlled by said two firstnamed means for moving said sight.

2. In combination, a gun, a sight therefor, a support for said gun and sight, means adapted to be set in accordance with the range of a target, means actuated in accordance with the anuglar velocity of said sight relative to said support, and means controlled by said two first-named moans for moving said sight to cause the latter to laofbehind said gun.

3. In combination., a gun, a sight therefor, a support for said gun, means for revolving said gun and means including a. part actuated by said gun and in accordance with the angular velocity thereof relative to said support for causing said sight to lag behind said gun.

4. Inicombination, a gun, a sight therefor, a Support for said gun, means for revolving said gun, means for causing said sight to la behind said gun, when the latter is revo ved on said support, to an extent dependent on the angular velocity of said gun relative to said support and means settable in accordance with the range ofa target and in acordance with the relative Wind velocity for varying the amount of lag of said sight.

5. In combination, a gun, a sightcarried thereby, a support for said gun, means forl revolving said gun relative to said support and means actuated by revolution of said gun for causing said sight to move with respect' to said gun in a direction opposite to theA direction of revolution of said gun.

6. In a gun sighting system for aircraft` a gun, a sighttherefor, a support for said gun, means positioned in accordance With a function of the angular velocity oflsaid gun in azimuth with respect to its support and means operatively connected to said first named means for deflccting said sight.

7. In a gun sighting system for air craft. a gun, a sight therefor, a support for said gun. means positioned in accordance with a function of the angular' velocity of `Said gun in azimuth with respect to its support, mechanism settable invaccordanee with the range of a relatively moving target and connections between said means. mechanism and sight for deflectingthe lat-ter.

8. The combination with a gun adapted to be tired from an aircraft and a sight therefor. of means positionedin accordance with a function of the angular velocity of said gun with respect to the aircraft. mechanism settablc in accordance with the air speed of thc/aircraft and connections between said means. mechanism and sight for (le-fleeting the latter.

9. The combination with a gun adapted to be fired from an aircraftA and a sight'. therefor. of means settable in accordance with the range of a relatively moving target, mechanism settable in accordance with the airspeed of the aircraft and connections between said means, mechanism and sight for deflecting the latter.

10. The combination with a gun adapted to be fired from an aircraft and a sight therefor, of an element positioned in accordance with a function of the angular velocity of said gun with respect to the aircraft. a second element settable in accordance with the range of a target, a third element; settable in accordance with the air speed of the aircraft and connections between said first, second and third elements and said sight for defiecting the latter.

11. In combination, a4 support, a gun revolubly mounted thereon, an element. positioned in accordance with a function of the angular velocity in azimuth of said gun with respect to its support, a second element positioned in accordance with the angular velocity of said gun with respect to, its support, a sight for said gun and connections between said elements and sight forI deflecting the latter.

12. The combination with a gun adapted to be tired from an aircraft and a sight therefor. of an clement positioned in accordance with a function of the instantaneous angular relationship of said gun with respect to the aircraft, a second element setta-ble in accordance with the air speed of the aircraft, a lthird element positioned in accordance with the angular velocity of said gun with respect to the aircraft, and means connecting said first, second and third elements and said sight for delecting the latter.

13. The combination with a gun adapted to be fired from an aircraft and a sight therefor, of an element-settable in accordance with the air speed of the aircraft, a second element positioned in accordance with the angular velocity of said gun with respectv to the aircraft and connta'tions bctween said elements and said sight for de fleeting the latter.

1l. The combination with a gun adapted to be firedl from an aircraft and a sight therefor. of an element positioned in accordance with the angular velocity of said gun with respect to the aircraft. a second element settable in accordance with the range of a relatively moving target. a device connected to said first and second elements and positioned in accordance with the combined movements thereof. a third clement posi 'tioned in accordance with a function of the angu'ar velocit \Y of said gun with respect to the aircraft. a fourth clement settable in accordance with the air speed of the aircraft. a second device connected to said second. third and fourth elements and positioned in accordance with the combined movements thereof and means connecting said first and second devices to said sight for causing a de.- iection of the lat-ter.

15. In combination. a gun. a sight therefor. means for changing the elevation of said sight with respect to said gun and an indicator visible through the eye-piece of said sight and connected vto said means.

16. In combination, a gun. a sight therefor, a support for said gun. a shaft connected to sai-d sight for detiecting the latter, a speed responsive device actuated onrevolution of said gun relative to said support and connections between said shaft and speed responsive device.

17. In combination, agun, asight therefor, a support for said gun` a shaft connected to said sight for deflecting the latter, a speed responsive devicel actuated on revolution of said gun relative to said support and means including a follow-up device connecting said shaft and speed responsive device.

1S. In combination, a. gun, a sight therefor. a support. for said gun. a shaft connectied to said sight for deflecting the. latter, a' speed responsive device actuated on revolution of said gun relative to said support, means comprising a lever connecting said shaft and device and means for changing the effective length of said lever in accordance with a function of the. range of a target.

19. In combination. a gun. a sight therefor. a differential having at least three arms. a connection between one of said arms and said sight, a speed responsive device, connections between another of the arms of the differential and said device` a manually settable member and connections between the third arm of said differential and said-member. f

20. In combination. a gun. a sight therefor, an element connected with said gun for revolutlon thereby. a member actuated by said element. manualy adjustable means for varying the path of movement of said member and connections between said member and sight.

2l. ln combination, a gun, a sight therefor, a support for said gun, an element posi-A tioned in accordance `With the angular velocity of said gun with respect to its support, a member connected tosaid element to be displaced thereby, means for varying the position of maximum displacement of-said member 'and connections between said member and sight. v

22. In combination. a support, a gun rotatably mounted on said support. an adjustable sight, mounted thereon, and means actuated by said gun in accordance with the angular -velocity of the latter for adjusting said sight with respect thereto.

23. In combination, a gun, a sight therefor, a support for said gun, means adapted to be set in accordance With the range of a Laenge@ support, and means cont-roled by said two.

first named means for actuating said sight in accordance with the product of said angu.

lar velocity and a function of the range.

24. In combination with a gun rotatably mounted, an adjustable sight thereon, a member connected to said gun for movement thereby, a follow-up member, power means, mechanical clutch means between said follow-up member andV power means, means called into action upon relative movemente of said members for rendering said clutch means operative, and means controlled by' said follow-up member for adjusting said sight.

In testimony whereof ll have afiixed my signature.

yELE/EER A. SPERRY: 

